[PATCH v2 4/5] drm/mediatek: Support "Pre-multiplied" blending in Mixer

From: Hsiao Chien Sung via B4 Relay
Date: Wed Jul 10 2024 - 04:38:15 EST


From: Hsiao Chien Sung <shawn.sung@xxxxxxxxxxxx>

Support "Pre-multiplied" alpha blending mode in Mixer.
Before this patch, only the coverage mode is supported.

To replace the default setting that is set in mtk_ethdr_config(),
we change mtk_ddp_write_mask() to mtk_ddp_write(), and this change will
also reset the NON_PREMULTI_SOURCE bit that was assigned in
mtk_ethdr_config(). Therefore, we must still set NON_PREMULTI_SOURCE bit
if the blend mode is not DRM_MODE_BLEND_PREMULTI.

Signed-off-by: Hsiao Chien Sung <shawn.sung@xxxxxxxxxxxx>
---
drivers/gpu/drm/mediatek/mtk_ethdr.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_ethdr.c b/drivers/gpu/drm/mediatek/mtk_ethdr.c
index 80ccdad3741b..d1d9cf8b10e1 100644
--- a/drivers/gpu/drm/mediatek/mtk_ethdr.c
+++ b/drivers/gpu/drm/mediatek/mtk_ethdr.c
@@ -36,6 +36,7 @@
#define MIX_SRC_L0_EN BIT(0)
#define MIX_L_SRC_CON(n) (0x28 + 0x18 * (n))
#define NON_PREMULTI_SOURCE (2 << 12)
+#define PREMULTI_SOURCE (3 << 12)
#define MIX_L_SRC_SIZE(n) (0x30 + 0x18 * (n))
#define MIX_L_SRC_OFFSET(n) (0x34 + 0x18 * (n))
#define MIX_FUNC_DCM0 0x120
@@ -176,6 +177,11 @@ void mtk_ethdr_layer_config(struct device *dev, unsigned int idx,
alpha_con |= state->base.alpha & MIXER_ALPHA;
}

+ if (state->base.pixel_blend_mode == DRM_MODE_BLEND_PREMULTI)
+ alpha_con |= PREMULTI_SOURCE;
+ else
+ alpha_con |= NON_PREMULTI_SOURCE;
+
if ((state->base.fb && !state->base.fb->format->has_alpha) ||
state->base.pixel_blend_mode == DRM_MODE_BLEND_PIXEL_NONE) {
/*
@@ -193,8 +199,7 @@ void mtk_ethdr_layer_config(struct device *dev, unsigned int idx,
mtk_ddp_write(cmdq_pkt, pending->height << 16 | align_width, &mixer->cmdq_base,
mixer->regs, MIX_L_SRC_SIZE(idx));
mtk_ddp_write(cmdq_pkt, offset, &mixer->cmdq_base, mixer->regs, MIX_L_SRC_OFFSET(idx));
- mtk_ddp_write_mask(cmdq_pkt, alpha_con, &mixer->cmdq_base, mixer->regs, MIX_L_SRC_CON(idx),
- 0x1ff);
+ mtk_ddp_write(cmdq_pkt, alpha_con, &mixer->cmdq_base, mixer->regs, MIX_L_SRC_CON(idx));
mtk_ddp_write_mask(cmdq_pkt, BIT(idx), &mixer->cmdq_base, mixer->regs, MIX_SRC_CON,
BIT(idx));
}

--
2.43.0